Stereoscopic image display device and stereoscopic image appreciation eyeglasses

ABSTRACT

An infrared polarizing filter is attached to an infrared synchronization signal radiator of a stereoscopic image display device which alternately displays right and left images by time-division with polarized light in one direction to radiate the polarized-light infrared synchronization signal. In order to solve the problem with the occurrence of crosstalk, stereoscopic image appreciation eyeglasses ( 30 ) are configured in such a manner that polarizing plates ( 33 ) are arranged side-by-side in the right and left visual fields, and visual field opening/closing liquid crystal cells ( 31 ) and tilt correcting liquid crystal cells ( 32 ) are arranged one on another on the front surfaces of the polarizing plates ( 33 ), that the polarized-light infrared synchronization signal is received by a synchronization signal receiver ( 37 ) mounted on an eyeglass frame, the visual field opening/closing liquid crystal cells ( 31 ) are driven in synchronization with each other, the right and left visual fields are alternately opened/closed relative to the display light of the stereoscopic image display device, and the voltage which is controlled by tilt angle data detected by a tilt angle detector mounted on the eyeglass frame according to the tilt of the eyeglasses is applied to the tilt correcting liquid crystal cells ( 32 ), and that the rotating light angle of the tilt correcting liquid crystal cells ( 32 ) is adjusted, and the shielded state at the time of closing the visual fields is always the maximum.

TECHNICAL FIELD

The present invention relates to a stereoscopic image display devicethat alternately displays right and left images composing a stereoscopicimage by time division with linear polarized light in one direction, andstereoscopic image appreciation eyeglasses for separating right and leftvisual fields of the displayed stereoscopic image to performstereoscopic viewing, and particularly, to the prevention of a crosstalkthat may occur when the linear polarized light is used.

BACKGROUND ART

Conventionally, to separate right and left visual fields of astereoscopic image, the right and left visual fields are displayed oneover the other (by projection) by right and left linear polarizedlights, which are orthogonal to each other, or right and left circularpolarized lights, which rotate in opposite directions, and areseparately viewed using polarization eyeglasses, the right and leftsides of which are orthogonal to each other, or circular polarizationeyeglasses, the right and left of which rotate in opposite directions,depending on a display system, to appreciate the stereoscopic image.However, in recent years, as a writing speed of a direct view typedisplay (particularly, an LCD (Liquid Crystal Display)) has increased,right and left images composing a stereoscopic image have beenalternately displayed by time division even in a direct view type LCDTV(Liquid Crystal Display Television) or the like, and an attempt toseparate right and left visual fields by visual field separatingeyeglasses (e.g., liquid crystal shutter eyeglasses) to performstereoscopic viewing has been made.

However, the liquid crystal shutter eyeglasses use two polarizing platesone over the other, and thus has the disadvantage in that transmittedlight is significantly attenuated and the visual fields become dark.Moreover, the shutter eyeglasses guide a light beam (polarized lightbeam), which has been transmitted by the polarizing plate on their frontsurface in a direction orthogonal to a direction of the polarizing plateon their rear surface when the visual fields are closed, to alternatelyopen and close the visual fields. Due to such a shutter function, anopening time becomes one-half or less and a light amount is attenuated.This shutter function intermits not only a stereoscopic image but alsosurrounding environmental light. Therefore, the problem that a flickeroccurs under illumination, which is turned on at a commercial frequency,has been pointed out.

In the direct view type display, the right and left images are difficultto simultaneously display (however, images to be displayed by polarizedlights in different directions for each line exist). Therefore, it hasalso been proposed that the right and left images are displayed by timedivision by linear polarized light in one direction and are separatelyviewed by devising eyeglasses on the appreciation side.

However, if the viewer tilts his/her head at his/her destiny usinglinear polarized light, it is difficult to avoid a program of acrosstalk (e.g., Patent literature 1).

Further, a person's eyesight (diopter) differs from individual toindividual. However, there are no existing stereoscopic imageappreciation eyeglasses including a diopter correction lens. Therefore,the stereoscopic image eyeglasses are overlaid on eyeglasses usuallyused when used in the present circumstances.

CITATION LIST Patent Literature

Patent Literature 1: Japanese patent Application Laid-Open No.2002-82307

SUMMARY OF INVENTION Technical Problem

As described in the foregoing column [background art], a problem ofappreciation eyeglasses for viewing a stereoscopic image of a type ofbeing displayed by time division on one screen includes the followingtwo points, as can be seen in liquid crystal shutter eyeglasses:

a: A visual field is dark.

b: A flicker occurs.

A method discussed in Patent literature 1 solves the above-mentioned twopoints in the problem occurring in the liquid crystal shutter eyeglasseswhile the following problem is newly raised:

c: A crosstalk occurs.

This occurs when a viewer tilts his/her head. The shutter eyeglassescompletely shield the visual fields using two polarizing platesorthogonal to each other when the visual fields are closed. On the otherhand, in the method discussed in Patent literature 1, the visual fieldsare shielded when closed by a polarizing plate provided in a televisionset (in an LCDTV, display light itself is polarized light so that a newpolarizing plate need not be provided on a front surface of theeyeglasses, as in Patent literature 1) and a polarizing plate in theeyeglasses. When the viewer tilts his/her head, therefore, an orthogonalstate between the polarized light from an LCD and the polarizing platein appreciation eyeglasses is destroyed. Thus, the occurrence of acrosstalk cannot be avoided.

If the stereoscopic image of a time division display type isappreciated, therefore, there occurs a technical subject to developstereoscopic image appreciation eyeglasses capable of normalstereoscopic viewing by simultaneously solving the above-mentioned threeproblems. Therefore, the present invention is directed to solving thissubject.

Solution to Problem

The invention as set forth in claim 1 provides a stereoscopic imagedisplay device that alternately displays right and left images by timedivision with polarized light in one direction, the stereoscopic imagedisplay device including an infrared light synchronization signalradiator for visual field opening/closing, and being further configuredto radiate polarized infrared light used as a basis for tilt correctionby attaching an infrared polarizing filter along the infrared lightsynchronization signal radiator for visual field opening/closing as abasis for tilt correction of stereoscopic image appreciation eyeglassesor separately installing the polarized infrared light radiator for tiltcorrection.

This configuration enables the polarized infrared light to be used as abasis for tilt correction of the stereoscopic image appreciationeyeglasses. If the right and left images are appreciated with thestereoscopic image appreciation eyeglasses for performing tiltcorrection using the polarized infrared light, a crosstalk can beprevented from occurring even if a viewer tilts his/her head.

The invention as set forth in claim 2 provides stereoscopic imageappreciation eyeglasses, for appreciating a stereoscopic image composedof right and left images to be alternately displayed by a time-divisionsystem with linear polarized light, the amplitude direction of which isone direction, the stereoscopic image appreciation eyeglasses beingconfigured so that polarizing plates in the same direction arerespectively arranged side by side in right and left visual fields ofthe eyeglasses, and a visual field opening/closing liquid crystal celland a tilt correcting liquid crystal cell for correcting the tilt of theeyeglasses are installed one over the other on a front surface of eachof the polarizing plates, to receive a polarized infrared lightsynchronization signal (which need not be polarized if it includes onlya synchronization signal) from a stereoscopic image display device by asynchronization signal receiver placed on an eyeglass frame tosynchronously drive the visual field opening/closing liquid crystalcells using the synchronization signal while driving and adjusting thetilt correcting liquid crystal cells installed on the right and leftvisual fields of the eyeglasses using detection data of a tilt angledetector placed on the eyeglass frame so that a light-shielded state atthe time of closing the visual fields always reaches its maximum evenwhen the eyeglasses are tilted during appreciation, to prevent acrosstalk from occurring.

According to this configuration, the tilt angle detector automaticallydetects the tilt of the eyeglasses for the display image of thestereoscopic image display device, and the tilt correcting liquidcrystal cell adjusts optical rotation of the display image according toa value obtained by the detection so that a tilted state isautomatically corrected to a state similar to a horizontal state.

The invention as set forth in claim 3 provides stereoscopic imageappreciation eyeglasses for appreciating a stereoscopic image composedof right and left images to be alternately displayed by a time-divisionsystem with linear polarized light, the amplitude direction of which isone direction, the stereoscopic image appreciation eyeglasses beingconfigured so that polarizing plates in the same direction arerespectively arranged side by side in right and left visual fields ofthe eyeglasses, and a liquid crystal cell is installed on a frontsurface of each of the polarizing plates, to calculate data representinga polarized infrared light synchronization signal radiated from astereoscopic image display device and received by an infrared lightsynchronization signal receiver placed on an eyeglass frame anddetection data of a tilt angle detector placed on the eyeglass frame,apply a voltage based on data obtained by the calculation to the liquidcrystal cells on the front surface of the eyeglasses to synchronouslydrive the liquid crystal cells, alternately open and close the right andleft visual fields for the stereoscopic image to separately view thestereoscopic image while causing a light-shielded state at the time ofclosing the visual fields to always reach its maximum even when theeyeglasses are tilted during appreciation, to prevent a crosstalk fromoccurring.

This configuration enables the configuration to be made simpler thanthat of the stereoscopic image appreciation eyeglasses as set forth inclaim 2.

The invention as set forth in claim 4 provides stereoscopic imageappreciation eyeglasses for appreciating a stereoscopic image composedof right and left images to be alternately displayed by a time-divisionsystem with linear polarized light, the amplitude direction of which isone direction, the stereoscopic image appreciation eyeglasses beingconfigured so that polarizing plates in the same direction arerespectively arranged side by side in right and left visual fields ofthe eyeglasses, and a total of six liquid crystal cells, three liquidcrystal cells overlaid on the right side and three liquid crystal cellsoverlaid on the left side each including a visual field opening/closingliquid crystal cell, a left tilt correcting liquid crystal cell, and aright tilt correcting liquid crystal cell, respectively, on frontsurfaces of the polarizing plates, to receive a synchronization signalradiated from an infrared light synchronization signal radiator attachedalong a stereoscopic image display device by an infrared lightsynchronization signal receiver placed on an eyeglass frame tosynchronously drive the visual field opening/closing liquid crystalcells, alternately open and close the right and left visual fields forthe stereoscopic image to separately view the stereoscopic image whiledriving and adjusting the left tilt correcting liquid crystal cells orthe right tilt correcting liquid crystal cells installed one over theother on each of the right and left visual fields of the eyeglasses, asneeded, using detection data of a tilt angle detector placed on theeyeglass frame so that a light-shielded state at the time of closing thevisual fields always reaches its maximum even when the eyeglasses aretilted during appreciation, to prevent a crosstalk from occurring.

This configuration enables a tilt correction range to be enlarged to awide range.

The invention as set forth in claim 5 provides a tilt angle detector fortilt correction of stereoscopic image appreciation eyeglasses, the tiltangle detector including a tilt angle detecting liquid crystal cell, aninfrared polarizing filter, and an infrared sensor, and being configuredas its functions so that a voltage to be applied to the tilt angledetecting liquid crystal cell, i.e., a checking voltage is graduallyraised, and an output of the infrared sensor rapidly decreases, to entera non-output state at the time point where the amplitude direction ofpolarized infrared light, which is optically rotated by the tilt angledetecting liquid crystal cell, enters a state orthogonal to thepolarization direction of the infrared polarizing filter, and a voltageapplied to the tilt angle detecting liquid crystal cell at the timepoint is sampled, to detect a tilt angle.

This configuration enables a tilt angle in a wide range (at a largeangle) to be accurately detected.

The invention as set forth in claim 6 provides a tilt angle detector fortilt correction of stereoscopic image appreciation eyeglasses, the tiltangle detector being configured so that a first tilt angle detectingliquid crystal cell and a second tilt angle detecting liquid crystalcell are installed one over the other to enlarge an operation range, aninfrared polarizing filter and an infrared sensor are arranged in thisorder behind the first and second tilt angle detecting liquid crystalcells, polarized infrared light radiated from a polarized infrared lightsynchronization signal radiator in a stereoscopic image display deviceis transmitted by the first tilt angle detecting liquid crystal cell andthe second tilt angle detecting liquid crystal cell after its opticalrotation has been adjusted thereby by applying a voltage to an electrodeof the first tilt angle detecting liquid crystal cell and an electrodeof the second tilt angle detecting liquid crystal cell after couplingthe electrodes in series or in parallel or sequentially applying avoltage to the electrode of the first tilt angle detecting liquidcrystal cell and the electrode of the second tilt angle detecting liquidcrystal cell, the applied voltage is gradually raised, an output of theinfrared sensor rapidly decreases to enter a non-output state at thetime point where the amplitude direction of the polarized infrared lightenters a state orthogonal to the polarization direction of the infraredpolarizing filter, and a voltage applied to the liquid crystal cells atthat time point is sampled, to detect a tilt angle.

This configuration enables an operation range to be further enlarged toa wider range than that of the tilt angle detector as set forth in claim5.

The invention as set forth in claim 7 provides a tilt angle detector fortilt correction of stereoscopic image appreciation eyeglasses, the tiltangle detector including infrared polarizing plates arranged side byside with their respective polarization directions tilted in oppositedirections using a vertical line as an axis of symmetry and infraredsensors respectively installed at positions just behind the infraredpolarizing plates, and being configured so that symmetry between thetilts of the infrared polarizing plates is destroyed when the eyeglassesare tilted so that a difference occurs in an amount of transmission ofpolarized infrared light serving as a basis for tilt correction, whichhas been radiated from a stereoscopic image display device, and thedifference is used as an electrical output using the infrared sensor, todetect a tilt angle.

This configuration enables the tilt angle detector to be implemented ina significantly simple configuration.

The invention as set forth in claim 8 provides stereoscopic imageappreciation eyeglasses, in which a slot for a diopter correction lensholder and a lens pressing spring are provided on a front surface or arear surface of the eyeglasses.

This configuration enables a stereoscopic image appreciation eyeglassestailored to the diopter of each of viewers by replacing the dioptercorrection lens.

The invention as set forth in claim 9 provides a diopter correction lenshaving both its ends formed in a circular arc shape and having its lowerend formed in the shape of a curve or a straight line having a largercurvature than that of the circular arc shape at both the ends.

This configuration enables the diopter correction lens to be easilydetachably attached while preventing the lens from rotating.

Advantageous Effects of Invention

The invention as set forth in claim 1 can embody a stereoscopic imagedisplay device that prevents a crosstalk in a simple configuration inwhich a polarized infrared light radiator is installed in a stereoscopicimage display device of a type of alternately displaying right and leftimages by time division with polarized light in one direction, or aninfrared polarizing filter is only attached along a synchronizinginfrared light radiator. The invention has the effect of implementingaccurate tilt angle detection and tilt correction with an electroopticalfunction by using polarized infrared light as a basis for tiltcorrection of stereoscopic image appreciation eyeglasses.

The invention as set forth in claim 2 has the effect of not causing acrosstalk even if liner polarized light is used as display light of astereoscopic image. Only one polarizing plate is used for eyeglasses.Therefore, a light amount is hardly attenuated. Moreover, surroundingenvironmental light is unpolarized light so that a function of theeyeglasses does not affect the surrounding environmental light. This hasthe effects of not decreasing illuminance of surrounding illuminationlight or the like and eliminating the need to wear and remove theeyeglasses in work performed while viewing a stereoscopic display. Theinvention also has the effect of not causing a flicker even underillumination using a discharge lamp that is turned on at a commercialfrequency.

Further, the invention has the advantage that a stable operation isensured even if an operation range for tilt correction is set largebecause a tilt correcting liquid crystal is separately provided.

The invention as set forth in claim 3 has a similar effect to that ofthe invention as set forth in claim 2, and has the effect of reducingthe number of constituent elements to be used, i.e., liquid crystalcells. However, an operation range for tilt correction inevitablynarrows.

The invention as set forth in claim 4 includes a left tilt correctingliquid crystal cell in a case where eyeglasses are tilted leftward and aright tilt correcting liquid crystal cell in a case where the eyeglassesare tilted rightward, and further has the effect of enlarging anoperation range for tilt correction to a wide range (901° or more) inaddition to the above-mentioned effect of claim 2 by using separateliquid crystal cells depending on a tilt direction.

The invention as set forth in claim 5 can rapidly detect an accuratetilt angle even if eyeglasses are greatly tilted. Therefore, theinvention has the effect of stably maintaining correction in a widerange. The invention also has the effects of eliminating the need forfine adjustment during manufacture and during use as seen in a tiltangle detector of a mechanical type and having no extra vibration or thelike.

The invention as set forth in claim 6 further has the effect ofenlarging an operation range for tilt angle detection to a wide range(90° or more) in addition to the effect of the tilt angle detector asset forth in claim 5 by applying a control voltage to a first tilt angledetecting liquid crystal cell and a second tilt angle detecting liquidcrystal cell serving as ones for tilt angle detection in series or inparallel after installing the liquid crystal cells one over the other orsequentially applying a voltage to an electrode of the first tilt angledetecting liquid crystal cell and an electrode of the second tilt angledetecting liquid crystal cell.

The invention as set forth in claim 7 has the effect of detecting atilted state even in a simple configuration and completely preventingthe occurrence of a crosstalk.

The invention as set forth in claim 8 further eliminates the need to usea diopter correction lens (eyeglasses usually used) and stereoscopicimage appreciation eyeglasses one over the other for a person whorequires a diopter correction lens in addition to the inventions as setforth in claims 2, 3, and 4. The invention also has the effect ofselecting an optimum diopter correction lens depending on a distancefrom an object to be viewed.

The invention as set forth in claim 9 has the effect of easily insertinga diopter correction lens into a slot for a diopter correction lensholder in stereoscopic image appreciation eyeglasses by forming bothends of a diopter correction lens in a circular arc shape. The circulararc shape has the effect of preventing the lens from dropping out of theslot, combined with a spring installed into a holder portion in theeyeglasses. Further, the lens itself is prevented from rotating byforming its lower end into a curve or a straight line having a largercurvature than that of a circular arc at both the ends. This has theeffect of an astigmatic axis not being changed if an astigmatic lens isused.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a stereoscopic TV according to thepresent invention.

FIG. 2 is a front view of stereoscopic image appreciation eyeglassesaccording to the present invention.

FIG. 3 is a diagram illustrating a configuration of stereoscopic imageappreciation eyeglasses according to the present invention.

FIG. 4 is a diagram illustrating an operating condition of thestereoscopic image appreciation eyeglasses according to the presentinvention.

FIG. 5 is a diagram illustrating another embodiment of the stereoscopicimage appreciation eyeglasses according to the present invention.

FIG. 6 is a diagram illustrating still another embodiment of thestereoscopic image appreciation eyeglasses according to the presentinvention.

FIG. 7( a) is a front view illustrating another embodiment of thestereoscopic image appreciation eyeglasses according to the presentinvention.

FIG. 7( b) is a diagram illustrating a configuration of a tilt angledetector illustrated in FIG. 7( a).

FIG. 8 is a front view illustrating an embodiment of stereoscopic imageappreciation eyeglasses along which a diopter correction lens holder isattached.

DESCRIPTION OF EMBODIMENTS

The concept of the present invention will be described with reference tothe drawings. FIG. 1 illustrates a stereoscopic image display device.The stereoscopic image display device includes an LCD stereoscopictelevision set (hereinafter referred to as a “stereoscopic TV”), forexample, and alternately display right and left images by time divisionon a display 14. Simultaneously, a polarized infrared lightsynchronization signal radiator 12 installed on a main body 11 of thestereoscopic TV 10 has an infrared polarizing filter 13 attached alongits surface, and generates a polarized infrared light synchronizationsignal.

FIG. 2 is a front view of stereoscopic image appreciation eyeglasses 20serving as an embodiment of stereoscopic image appreciation eyeglassesaccording to the present invention. Right and left identical polarizingplates 23 _(R) and 23 _(L), the polarization direction of which has beentilted by 45° from the polarization direction of the display 14 in theabove-mentioned stereoscopic TV 10, are arranged side by side, asillustrated, respectively, in right and left visual fields of theeyeglasses.

Further, two types of liquid crystal cells, i.e., visual fieldopening/closing liquid crystal cells 21 _(R) and 21 _(L) and tiltcorrecting liquid crystal cells 22 _(R) and 22 _(L) are respectivelyinstalled one over the other, respectively, on front surfaces of thepolarizing plates 23 _(R) and ² 3 _(L). An infrared lightsynchronization signal receiver 27 and a tilt angle detector (a tiltangle detecting liquid crystal cell 24, an infrared polarizing filter25, and an infrared sensor 26) are provided on an eyeglass frame.

FIG. 3 is a diagram illustrating a configuration of the stereoscopicimage appreciation eyeglasses illustrated in FIG. 2. An infrared lightsynchronization signal receiver 37, as illustrated, receives asynchronization signal using polarized infrared light (thesynchronization signal need not be polarized) radiated via the infraredpolarizing filter 13 in the stereoscopic TV 10. The receivedsynchronization signal is sent to a controller C1, and is converted intoa control voltage therein. The control voltage is applied to visualfield opening/closing liquid crystal cells 31 _(R) and 31 _(L). Thus,visual fields of the stereoscopic image appreciation eyeglasses 30 areopened and closed in synchronization with display images that arealternately displayed by time division on the display 14 in thestereoscopic TV 10.

If a viewer tilts his/her head, an orthogonal state between theamplitude direction of the display image, optical rotation of which hasbeen adjusted to open and close the visual fields, and polarizing plates33 _(R) and 33 _(L) is destroyed, to enter a state where a crosstalkoccurs. However, a configuration, using tilt correcting liquid crystalcells 32 _(R) and 32 _(L), of a tilt angle detector (including a tiltangle detecting liquid crystal cell 34, an infrared polarizing filter35, and an infrared sensor 36) according to the present invention,illustrated in FIG. 3, is proposed to prevent the crosstalk fromoccurring by correcting the tilt of the eyeglasses. The tilt angledetector adjusts optical rotation of the polarized infrared lightsynchronization signal generated from the infrared polarizing filter 13in the stereoscopic TV 10 using the tilt angle detecting liquid crystalcell 34 and analyzes the synchronization signal using the infraredpolarizing filter 35, to detect a tilt angle. If such a function isdescribed, a controller C2 first applies a voltage periodically (e.g.,about several times per second) to the tilt angle detecting liquidcrystal cell 34. If the applied voltage is gradually raised, anoptically rotated state occurring by the tilt angle detecting liquidcrystal cell 34 changes, and the amplitude direction of the polarizedinfrared light, which has been transmitted by the tilt angle detectingliquid crystal cell 34, enters a state orthogonal to the polarizationdirection of the infrared polarization filter 35. If the orthogonalstate occurs, an output of the infrared sensor 36 rapidly decreases toenter a non-output state, to detect a tilt angle. A voltage applied tothe tilt angle detecting liquid crystal cell 34 by the controller C2 atthis time point is sampled, to detect a tilt angle.

Data representing the above-mentioned detected tilt angle for tiltcorrection is converted into a control voltage by the controller C2, andthe control voltage is applied to the tilt correcting liquid crystalcells 32 _(R) and 32 _(L). If the viewer tilts his/her head, theorthogonal state at the time of closing the visual fields is destroyed,and a light beam to be blocked slightly slips through the polarizingplates 33 _(R) and 33 _(L) so that a crosstalk occurs. However,according to the present invention, the crosstalk, i.e., leaked light iscorrected by the tilt correcting liquid crystal cells 32 _(R) and 32_(L), to enter a state completely orthogonal to the polarizing plates 33_(R) and 33 _(L). Thus, a light-shielded state at the time of closingthe visual fields is always maintained at a maximum.

FIG. 4 is a diagram illustrating an optically rotated state of thestereoscopic image appreciation eyeglasses 30. If display light by thedisplay 14 in the stereoscopic TV illustrated in FIG. 1, describedabove, is polarized light vibrating in a horizontal direction, forexample, the display light is incident on right and left visual fieldsof the eyeglasses illustrated in FIG. 4. In the left visual field, novoltage is applied to a visual field opening/closing liquid crystal cell41 _(L) because a switch, as illustrated, is in an opened state so thatthe display light vibrating in the horizontal direction is transmittedby the visual field opening/closing liquid crystal cell 41 _(L) afterbeing optically rotated by 90° therein, to vibrate in a vertical(up-and-down) direction. On the other hand, in the right visual field, avoltage is applied to a visual field opening/closing liquid crystal cell41 _(R) because a switch, as illustrated, is in a closed state so thatthe display light is transmitted by a visual field opening/closingliquid crystal cell 41 _(R) in the state of vibrating in the horizontaldirection. The right and left switches are actually set to bealternately opened and closed automatically in synchronization with thedisplay light in response to the infrared light synchronization signal.Therefore, the display lights, which have been transmitted by the visualfield opening/closing liquid crystal cells 41 _(R) or 41 _(L), arealways in a state orthogonal to each other between the right and leftvisual fields. (However, if the right and left visual fields of thestereoscopic image appreciation eyeglasses are also switchedsimultaneously with the switching of the right and left images to bealternately displayed by time division on an LCD of the stereoscopic TV,the right and left images of the stereoscopic TV may interfere with eachother. To avoid the interference, the right and left visual fields ofthe eyeglasses need to be simultaneously closed for a predeterminedperiod (a period slightly longer than a period of time during which theright and left images of the stereoscopic TV are switched) at the timepoint where the right and left images of the stereoscopic TV areswitched. Therefore, the display lights may not instantaneously be inthe orthogonal state.) A method for turning off a backlight of thestereoscopic TV when the visual fields of the eyeglasses are switched isalso implemented. An arrow representing the amplitude direction, on thenear side of each of the liquid crystal cells, of the display light isindicated by a solid line, and an arrow representing the amplitudedirection, on the far side thereof, of the display light is indicated bya broken line.

The right and left display lights, which have been transmitted by thevisual field opening/closing liquid crystal cells 41, as describedabove, are respectively incident on tilt correcting liquid crystal cells42 with the amplitude directions being orthogonal to each other. Asillustrated in FIG. 4, for example, the display light is incident in thestate of vibrating in a vertical (up-and-down) direction in the leftvisual field. At this time, the display light is incident in the stateof vibrating in a horizontal (right-and-left) direction in the rightvisual field. If the tilt correcting liquid crystal cell 42 is a TN modeliquid crystal, for example, and its operation range (angle) is 90°, abias voltage is always applied to the tilt correcting liquid crystalcell 42 so that the display light enters the state of being opticallyrotated by 45° that is one-half of 90°. The controller C2 converts datarepresenting the above-mentioned detected tilt angle data into a controlvoltage, and adds and subtracts the control voltage to and from the biasvoltage, to drive the tilt correcting liquid crystal cell 42. Since thetilt correcting liquid crystal cells 42 _(R) and 42 _(L) are driven inparallel (in the same direction and simultaneously on the right and leftsides), the display lights in the right and left visual fields aremaintained in a state orthogonal to each other even after beingtransmitted by the tilt correcting liquid crystal cells 42. For example,the display light, which has been transmitted by the visual fieldopening/closing liquid crystal cell 41 _(L) in the left visual field,vibrates in the vertical direction, and is directed toward thepolarizing plate 43 _(L) in the state of being optically rotated by 45°by the tilt correcting liquid crystal cell 42 _(L) (being maintained at45° by the bias voltage). The polarization direction of the polarizingplate 43 _(L) is fixed to 45° parallel to the amplitude direction of thedisplay light, which has been transmitted by the tilt correcting liquidcrystal cell 42 _(L). Therefore, the display light is transmitted by thepolarizing plate 43 _(L), to enter a visual field opened state. On theother hand, the amplitude direction of the display light, which has beentransmitted by the tilt correcting liquid crystal cell 42 _(R) in theright visual field, is in a state orthogonal to that in the left visualfield. Thus, the amplitude direction of the display light enters a stateorthogonal to the right polarizing plate 43 _(R) disposed with itspolarization direction being parallel to the left polarizing plate 43_(L). Therefore, the display light cannot be transmitted by thepolarizing plate 43 _(R), to enter a visual field closed state.

As described above, the stereoscopic image appreciation eyeglasses 30illustrated in FIG. 3 in the present invention perform a shutterfunction for stereoscopic image display light of the stereoscopic TV 10illustrated in FIG. 1. However, ambient light (surrounding environmentallight) is non-polarized light, and vibrates in all directions orthogonalto its travel direction. Therefore, the ambient light is affected byneither the visual field opening/closing liquid crystal cell 31 _(R) and31 _(L) nor the tilt correcting liquid crystal cells 32 _(R) and 32_(L). Therefore, there is no decrease in light amount by the shutterfunction (conventional liquid crystal shutter eyeglasses also have ashutter function for environmental light, and respective light amountsin right and left visual fields are one-half or less if the right andleft visual fields are alternately opened and closed). The fact thatthere is no shutter function for the surrounding environmental lightalso has the effect of not causing a flicker due to interference withillumination light. Moreover, only one polarizing plate is used so thatnot only the stereoscopic TV but also all the visual fields including asurrounding environment look bright. Therefore, this is significantlyadvantageous in stereoscopic view involving work.

If the stereoscopic image display light, the amplitude direction ofwhich is a horizontal direction, is transmitted by the visual fieldopening/closing liquid crystal cells 31 _(R) and 31 _(L), the amplitudedirection of the transmitted light is either a horizontal direction or avertical direction in the right and left visual fields. Morespecifically, the visual field takes two values, i.e., “opened” or“closed”. An intermediate value other than the two values is notpreferable because a visual field becomes dark or a crosstalk occurs.Accordingly, the visual field opening/closing liquid crystal needs to behigh in response speed. A II-type (OCB (Optically CompensatedBirefringence)) liquid crystal, or a ferroelectric liquid crystal(SSFLCD (Surface Stabilized Ferroelectric Liquid Crystal Device),PSS-LCD (Polarization Shielded Smectic Liquid Crystal Device)) issuitable for such an application.

A case where the eyeglasses are put horizontally has been describedabove. The polarizing plates 33 _(R) and 33 _(L), together with theeyeglasses, are tilted with the eyeglasses tilted so that theirrespective tilt angles are different from the above-mentioned angle of45°. Therefore, the orthogonal state at the time of closing the visualfields is destroyed. If this remains so, a crosstalk occurs. If theeyeglasses are tilted, therefore, the light-shielded state at the timeof closing the visual fields is always maintained at a maximum bydetecting the tilt angle of the eyeglasses using a tilt angle sensorplaced on the eyeglasses, and adding or subtracting a tilt correctingcontrol voltage to or from a bias voltage, to correct the amplitudedirection of the display light directed toward the polarizing plates 33_(R) and 33 _(L) to always enter a state orthogonal to the polarizationdirection of the polarizing plates 33 _(R) and 33 _(L) when the visualfields are closed.

While the tilt of the eyeglasses has been corrected by detecting thetilt angle to adjust an optically rotatable state by the tilt correctingliquid crystal cells 32 _(R) and 32 _(L), a checking voltage may beapplied to the tilt angle detecting liquid crystal cell 34 (by thecontroller C2) at a frequency of approximately several times per second.This is because a person does not shake his/her head at a so high speedwhen the person tilts his/her head. Even in a period during which thechecking voltage is not applied to the tilt angle detecting liquidcrystal cell 34 because the tilt angle is intermediately detected,however, corrected states of the tilt correcting liquid crystal cells 32_(R) and 32 _(L) need to be held in a certain state. The correctedstate, which has been updated when the tilt angle is detected, is helduntil the next tilt angle is detected, and such an operating conditionis always repeatedly continued so that a visually tilted state is alwaysmaintained in a horizontal state even if the stereoscopic imageappreciation eyeglasses are tilted in any direction. Therefore, acrosstalk is prevented from occurring.

While the tilt correcting liquid crystal cell 32 _(R), 32 _(L) isdisposed behind the visual field opening/closing liquid crystal cell 31_(R), 31 _(L) in the embodiment described in FIG. 3 in the presentinvention, either one of the liquid crystal cells may be disposed behindthe other liquid crystal cell.

A high response speed is not required for the tilt correcting liquidcrystal cells 32 _(R) and 32 _(L). This is because the speed at whichthe person tilts his/her head is significantly lower than a responsespeed of the liquid crystal, as described above. Therefore, aconventional TN mode liquid crystal is sufficient. Since an operationrange (for optical rotation) of the TN mode liquid crystal is 90°, anintermediate position between a position where the head is tiltedrightward and a position where the head is tilted leftward is ahorizontal position, a voltage maybe applied (a bias voltage) so thatthe tilt correcting liquid crystal cell 32 enters a state of beingoptically rotated by 45°, which is an intermediate value, with theeyeglasses horizontally put.

There is a case where respective applied voltages and characteristics ofoptically rotated states of the tilt angle detecting liquid crystal cell34 and the tilt correcting liquid crystal cells 32 _(R) and 32 _(L) maybe unproportional to each other. However, in the case, an opticalrotation angle can be accurately controlled by a program in which acorrected value is adjusted depending on a parameter in the controllerC2.

FIG. 5 illustrates another embodiment of stereoscopic image appreciationeyeglasses. On a frame of stereoscopic image appreciation eyeglasses 50illustrated in FIG. 5, a tilt angle detector including a tilt angledetecting liquid crystal cell 54, an infrared polarizing filter 55, andan infrared sensor 56 is placed. The stereoscopic image appreciationeyeglasses are configured to calculate detection data of the tilt angledetector and synchronization signal data of a synchronization signalreceiver 57 (a tilt angle detecting method and a synchronization signalreceiving method themselves are identical to those according to claim 2,described above) using a controller C, synchronously drive visual fieldopening/closing and tilt correcting liquid crystal cells 51 _(R) and 51_(L), alternately open and close visual fields for display light of thestereoscopic image display device 10 to perform stereoscopic viewingwhile performing control so that the display light of the stereoscopicimage display device, which has been transmitted by the visual fieldopening/closing and tilt correcting liquid crystal cells 51 _(R) and 51_(L), always enter a state orthogonal to the polarization directions ofpolarizing plates 53 _(R) and 53 _(L) when the visual fields are closedso that a light-shielded state at the time of closing the visual fieldsalways reaches its maximum, to prevent a crosstalk from occurring.

While high-speed responsiveness is required as a material for the visualfield opening/closing and tilt correcting liquid crystal cells 51 _(R)and 51 _(L) in the stereoscopic image appreciation eyeglasses having theabove-mentioned configuration, an SSFLCD cannot be used. This is becausethe SSFLCD has a sharp function and cannot display an intermediate value(cannot perform tilt correction). The stereoscopic image appreciationeyeglasses in the configuration according to claim 3 can be made smallerin the number of parts while being slightly narrower in a tiltcorrection range than in the above-mentioned configuration according toclaim 2.

As a tilt angle detector required to apply a correcting voltage to thetilt correcting liquid crystal cells 32 _(R) and 32 _(L) illustrated inFIG. 3 and the liquid crystal cells 51 _(R) and 51 _(L) illustrated inFIG. 5 in the present invention, described above, a gravity sensor (of atype of detecting an angle of a pendulum or the like and finallyconverting the angle into an electrical output or a type of finallyconverting a change in a liquid surface into an electrical output usinga liquid surface) and a gyro sensor (e.g., a piezoelectric gyro) can beused. Since the sensors can independently detect the tilt angle ofeyeglasses, polarized infrared light serving as a basis for tiltcorrection is not required. Therefore, the infrared polarizing filter 13in the stereoscopic TV 10 illustrated in FIG. 1 is not required in thecase.

FIG. 6 illustrates another embodiment of stereoscopic image appreciationeyeglasses according to the present invention, where polarizing plates63 are respectively arranged side by side in right and left visualfields of the eyeglasses. A left tilt correcting liquid crystal cell 62and a right tilt correcting liquid crystal cell 68, which are oppositein torsional direction, are installed one over the other on a frontsurface of the polarizing plate 63. Further, a visual fieldopening/closing liquid crystal cell 61 is further installed on the frontsurface of the left tilt correcting liquid crystal cell 62. Asynchronization signal receiver 67 receives an infrared lightsynchronization signal radiated from the polarized infrared lightsynchronization signal radiator 12 in the stereoscopic TV 10 illustratedin FIG. 1, and a controller C1 converts the synchronization signal intoa control voltage and applies the control voltage to the visual fieldopening/closing liquid crystal cells 61 _(R) and 61 _(L), to open andclose right and left visual fields. A state of right and left displaylights in this case is equal to that when the right and left displaylights are respectively transmitted by the visual field opening/closingliquid crystal cells 41 _(R) and 41 _(L), described with reference toFIG. 4. In this state, the right and left display lights are in a statewhere their respective amplitude directions are always orthogonal toeach other. The polarized right and left display lights, which vibratein a state orthogonal to each other, are transmitted by the left tiltcorrecting liquid crystal cells 62 _(R) and 62 _(L) and the right tiltcorrecting liquid crystal cells 68 _(R) and 68 _(L). If no voltage isapplied to the left tilt correcting liquid crystal cells 62 _(R) and 62_(L) and the right tilt correcting liquid crystal cells 68 _(R) and 68_(L) however, the display lights are optically rotated once by the lefttilt correcting liquid crystal cells 62 _(R) and 62 _(L) while beingreturned by the right tilt correcting liquid crystal cells 68 _(R) and68 _(L), which is opposite in torsional direction to the left tiltcorrecting liquid crystal cells 62 _(R) and 62 _(L). This is the same asa state where the left tilt correcting liquid crystal cells 62 _(R) and62 _(L) and the right tilt correcting liquid crystal cells 68 _(R) and68 _(L) are not installed. Right and left images, which are analyzed bythe polarizing plates 63 _(R) and 63 _(L) and are displayed by timedivision on the display 14 in the stereoscopic TV 10, are separated.

In the above-mentioned state, if the eyeglasses are tilted, anorthogonal state between the amplitude direction of the display lightsat the time of closing the visual fields and the polarization directionof the polarizing plates 63 _(R) and 63 _(L) is destroyed so that acrosstalk may occur. In such a case, a TN (Twisted Nematic) mode liquidcrystal is used for the left tilt correcting liquid crystal cells 62_(R) and 62 _(L) and right tilt correcting liquid crystal cells 68 _(R)and 68 _(L), for example. The left tilt correcting liquid crystal cells62 _(R) and 62 _(L) perform correction when the eyeglasses are tiltedleftward, and the right tilt correcting liquid crystal cells 68 _(R) and68 _(L) perform correction when the eyeglasses are tilted rightward sothat the tilt of the eyeglasses can be corrected by a total of 180°, 90°rightward and 90° leftward. In this case, a bias need not be applied tothe left tilt correcting liquid crystal cells 62 _(R) and 62 _(L) andthe right tilt correcting liquid crystal cells 68 _(R) and 68 _(L). Ifan STN (Super Twisted Nematic) mode liquid crystal is used instead of acase where two TN mode liquid crystals are used one over the other, thenumber of light crystal cells may be one. Two TN mode liquid crystalsare to be used one over the other in consideration of the need to applya bias thereto when the posture of the eyeglasses is in a horizontalstate, and a problem of color displacement and a difficulty of fineadjustment because of a steep tilt, which are characteristic of the STNmode liquid crystal.

To correct the tilt by a total of 180°, 90° rightward and 90° leftward,described above, a tilt angle of 180° needs to be detected. A first tiltangle detecting liquid crystal cell 64 and a second tilt angle detectingliquid crystal cell 69, which are illustrated as a tilt angle detectorin FIG. 6, can also be optionally rotated by 180° if one STN mode liquidcrystal is used. The problem of color displacement is ignored if the STNmode liquid crystal is for tilt angle detection. However, the STN modeliquid crystal is unsuitable because it is difficult to finely adjustbecause its tilt is steep. Therefore, a controller C2 applies a voltageto the first tilt angle detecting liquid crystal cells 64 and the secondtilt angle detecting liquid crystal cell 69, as illustrated, afteroverlaying the first tilt angle detecting liquid crystal cell 64 and thesecond tilt angle detecting liquid crystal cell 69 in a state, asillustrated, while coupling respective electrodes of the first tiltangle detecting liquid crystal cell 64 and the second tilt angledetecting liquid crystal cell 69 in a series state or a parallel state.The applied voltage is gradually raised so that polarized infrared lightthat is transmitted by the first tilt angle detecting liquid crystalcell 64 and the second tilt angle detecting liquid crystal cell 69,which are doubly overlaid, are adjusted to be optically rotated by 0 to180°. Accordingly, the tilt angle is detected by applying a voltage tothe first tilt angle detecting liquid crystal cell 64 and the secondtilt angle detecting liquid crystal cell 69 after coupling the liquidcrystal cells 64 and 69 in series or in parallel, and sampling a voltageat the time point where an output of an infrared sensor 66, asillustrated, rapidly decreases to enter a non-output state. A tilt angleof a total 180°, 90° rightward and 90° leftward, can be detected by asimilar function to that in the method for detecting the tilt angle ofthe stereoscopic image appreciation eyeglasses having theabove-mentioned configuration illustrated in FIG. 3. Naturally, avoltage applied when the first tilt angle detecting liquid crystal cell64 and the second tilt angle detecting liquid crystal cell 69 arecoupled in series becomes two times that when they are coupled inparallel (in a case where their respective optical rotation functionsare the same). Even if a voltage is applied to either one of the firsttilt angle detecting liquid crystal cell 64 and the second tilt angledetecting liquid crystal cell 69, and a voltage is sequentially appliedto the other tilt angle detecting liquid crystal cell when the appliedvoltage reaches (exceeds) a prescribed maximum value, a similar functionto that when the first and second tilt angle detecting liquid crystalcells 64 and 69 are coupled in serial or in parallel is produced.

When the left tilt correcting liquid crystal cells 62 _(R) and 62 _(L)and the right tilt correcting liquid crystal cells 68 _(R) and 68 _(L),which are respectively installed in visual fields of the eyeglasses, aretilted leftward or rightward from a horizontal state, they are set toseparately operate for leftward tilt or rightward tilt so that a biasneed not be applied thereto.

FIG. 7 illustrates a content discussed in Japanese Patent Laid-Open No.2009-274002 (stereoscopic image appreciation eyeglasses) previouslyfiled by the present applicant, where a polarizing plate 72 in avertical (up-and-down) direction is installed in right and left visualfields of eyeglasses illustrated in FIG. 7( a). Liquid crystal cells 71_(R) and 71 _(L) are attached to a front surface of the polarizing plate72. FIG. 7( b) is a detailed view of a synchronization signal receiver73 for opening and closing the visual fields of the eyeglasses insynchronization with a display image for a stereoscopic TV, andillustrates a method for detecting a tilt angle. Its functions will bedescribed below.

The infrared polarizing filter 13 on the radiation surface of theinfrared light synchronization signal radiator 12 attached along thestereoscopic image display device 10 illustrated in FIG. 1 changessynchronizing infrared light into polarized infrared light. Thepolarization direction of infrared polarizing filters 74 _(R) and 74_(L) in the synchronization signal receiver 73 is arranged in asymmetrically tilted state, as illustrated in FIG. 7( a) when theeyeglasses are put horizontally. In this case, respective outputs ofinfrared sensors 75 _(R) and 75 _(L) are equal to each other. If theeyeglasses are tilted either rightward or leftward from this state, adifference occurs between the outputs of the infrared sensors 75 _(R)and 75 _(L). A tilt angle can be detected by previously examining arelationship between the output difference and the tilt.

FIG. 8 illustrates a diopter correction lens optionally attached alongstereoscopic image appreciation eyeglasses and an attachment portion. Aperson's eyesight (diopter) differs from individual to individual. Evenin a usual life, many persons use diopter correcting eyeglasses. Even inan object to be viewed, there are a case where a small screen of apersonal computer is viewed at a close distance and a case where arelatively large TV is viewed at a slightly far distance. The need toswitch eyeglasses depending on a distance from the object also arises.Particularly, a person using reading glasses needs to change the diopterof a correction lens (replace eyeglasses usually used) depending on adistance from the object to be viewed. Accordingly, in stereoscopicimage appreciation eyeglasses, i.e., visual field separating eyeglasses,diopter correcting eyeglasses need to be used from individual toindividual. However, in the actual situation, the stereoscopic imageappreciation eyeglasses are overlaid on the eyeglasses usually used.However, using two types of eyeglasses one over the other is unstable,and is troublesome. Therefore, stereoscopic image appreciationeyeglasses for personal use incorporating a diopter correction lenstailored to the individual can also be prepared. However, a problemoccurring when the diopter correction lens is fixed, tailored to theindividual is that the stereoscopic image appreciation eyeglasses forpersonal use cannot be diverted to one for another person (theirrespective diopters do not match each other). The stereoscopic imageappreciation eyeglasses need to be changed depending on an object (a TVor a PC) to be viewed even for personal use.

The best method for solving the above-mentioned problem is to provide aslot for a lens holder on a front surface or a rear surface of thestereoscopic image appreciation eyeglasses and insert the dioptercorrection lens, as needed. FIG. 8 illustrates a holder (a slot) forretaining the diopter correction lens on the front surface of thestereoscopic image appreciation eyeglasses. The holder is moldedintegrally with an eyeglass frame (illustration of its main body portionis omitted). A holder portion 80, as illustrated, is provided with aslot 84 into which diopter correction lenses 81 _(R) and 81 _(L) are tobe inserted. The diopter correction lenses 81 _(R) and 81 _(L), whichhave been inserted into the slot 84, are pressed against the slot 84using a leaf spring 82. The diopter correction lenses 81 _(R) and 81_(L), which have been simultaneously inserted once, do not easily dropoff even if the eyeglasses are turned upside down by a shape of the leafspring 82 and a spring effect.

The diopter correction lens 81 has its right and left ends formed in acircular arc shape. The circular arc shape makes insertion into the slot84 easy. Further, upper and lower ends of the diopter correction lens 81are formed in a linear shape, to prevent the diopter correction lenses81 _(R) and 81 _(L) from rotating (functionally, only the lower end mayhave a linear shape). Such a rotation preventing function issignificantly effective when an astigmatic lens is required as thediopter correction lens. This is because astigmatism correction isperformed in a specific direction (angle) so that the diopter correctionlens needs to be fixed at a specific position in a rotational direction.A knob 83, as illustrated, has a structure in which aluminum is foldedand held therein or is bonded thereto, and can identify the lens byincreasing a frictional force against fingers when it is detachablyattached to the slot 84 and not only preventing the lens from beingcontaminated but also being marked.

The stereoscopic image appreciation eyeglasses according to the presentinvention do not react with ambient light. Therefore, a work environmentvisual field looks bright in work performed while observing astereoscopic image. Therefore, the eyeglasses need not be removed evenduring work other than viewing of a monitor. The function and effect ofthe stereoscopic image appreciation eyeglasses having this configurationare great.

Various modifications can be made as long as they do not depart from thespirit of the present invention, and the present invention naturallycovers the modifications.

INDUSTRIAL APPLICABILITY

Stereoscopic image appreciation eyeglasses according to the presentinvention are particularly visual field separating eyeglasses forseparating right and left visual fields of a stereoscopic image, whichis displayed by time division on a television set made of an LCD or apersonal computer, to perform stereoscopic viewing, and will behereafter essential in applications from general appreciation of astereoscopic image to appreciation of a stereoscopic image such asvarious types of simulation, education and training, inspection, medicalcare, and advertisement.

REFERENCE SIGNS LIST

-   -   10 stereoscopic image display device    -   11 stereoscopic image display device main body    -   12 polarized infrared light synchronization signal radiator    -   13 infrared polarizing filter    -   14 display    -   20 stereoscopic image appreciation eyeglasses    -   21 _(R), 21 _(L) visual field opening/closing liquid crystal        cell    -   22 _(R), 22 _(L) tilt correcting liquid crystal cell    -   23 _(R), 23 _(L) polarizing plate    -   24 tilt angle detecting liquid crystal cell    -   25 infrared polarizing filter    -   26 infrared sensor    -   27 synchronization signal receiver    -   C1 visual field opening/closing controller    -   C2 tilt correcting controller    -   30 stereoscopic image appreciation eyeglasses    -   31 _(R), 31 _(L) visual field opening/closing liquid crystal        cell    -   32 _(R), 32 _(L) tilt correcting liquid crystal cell    -   33 _(R), 33 _(L) polarizing plate    -   34 tilt angle detecting liquid crystal cell    -   35 infrared polarizing filter    -   36 infrared sensor    -   37 synchronization signal receiver    -   41 _(R), 41 _(L) visual field opening/closing liquid crystal        cell    -   42 _(R), 42 _(L) tilt correcting liquid crystal cell    -   43 _(R), 43 _(L) polarizing plate    -   50 stereoscopic image appreciation eyeglasses    -   C visual field opening/closing and tilt correcting controller    -   51 _(R), 51 _(L) visual field opening/closing and tilt        correcting liquid crystal cell    -   53 _(R), 53 _(L) polarizing plate    -   54 tilt angle detecting liquid crystal cell    -   55 infrared polarizing plate    -   56 infrared sensor    -   57 synchronization signal receiver    -   60 stereoscopic image appreciation eyeglasses    -   61 _(R), 61 _(L) visual field opening/closing liquid crystal        cell    -   62 _(R), 62 _(L) left tilt correcting liquid crystal cell    -   63 _(R), 63 _(L) polarizing plate    -   64 first tilt angle detecting liquid crystal cell    -   65 infrared polarizing filter    -   66 infrared sensor    -   67 synchronization signal receiver    -   68 _(R), 68 _(L)right tilt correcting liquid crystal cell    -   69 second tilt angle detecting liquid crystal cell    -   71 _(R), 71 _(L) visual field opening/closing and tilt        correcting liquid crystal cell    -   72 _(R), 72 _(L) polarizing plate    -   73 infrared light synchronization signal receiver    -   74 _(R), 74 _(L) infrared polarizing plate    -   75 _(R), 75 _(L) infrared sensor    -   80 lens holder    -   81 _(R), 81 _(L) diopter correction lens    -   82 leaf spring    -   83 knob    -   84 slot portion

1. A stereoscopic image display device that alternately displays rightand left images by time division with polarized light in one direction,the stereoscopic image display device comprising an infrared lightsynchronization signal radiator for visual field opening/closing, andbeing configured to radiate polarized infrared light used as a basis fortilt correction by attaching an infrared polarizing filter along theinfrared light synchronization signal radiator for visual fieldopening/closing as a basis for tilt correction of stereoscopic imageappreciation eyeglasses or separately installing a polarized infraredlight radiator for tilt correction.
 2. Stereoscopic image appreciationeyeglasses for appreciating a stereoscopic image by a stereoscopic imagedisplay device of a type of alternately displaying right and left imagescomposing the stereoscopic image by time division with linear polarizedlight, the amplitude direction of which is one direction, thestereoscopic image appreciation eyeglasses being configured so thatpolarizing plates in the same direction are respectively arranged sideby side in right and left visual fields of the eyeglasses, and a visualfield opening/closing liquid crystal cell and a tilt correcting liquidcrystal cell for correcting the tilt of the eyeglasses are installed oneover the other on a front surface of each of the polarizing plates, toreceive a synchronization signal radiated from an infrared lightsynchronization signal radiator attached along the stereoscopic imagedisplay device by an infrared light synchronization signal receiverplaced on an eyeglass frame to synchronously drive the visual fieldopening/closing liquid crystal cells, and to alternately open and closethe right and left visual fields for the stereoscopic image toseparately view the stereoscopic image while driving and adjusting thetilt correcting liquid crystal cells installed on the right and leftvisual fields of the eyeglasses using detection data of a tilt angledetector placed on the eyeglass frame so that a light-shielded state atthe time of closing the visual fields always reaches its maximum evenwhen the eyeglasses are tilted during appreciation, to prevent acrosstalk from occurring.
 3. Stereoscopic image appreciation eyeglassesfor appreciating a stereoscopic image by a stereoscopic image displaydevice of a type of alternately displaying right and left imagescomposing the stereoscopic image by time division with linear polarizedlight, the amplitude direction of which is one direction, thestereoscopic image appreciation eyeglasses being configured so thatpolarizing plates in the same direction are respectively arranged sideby side in right and left visual fields of the eyeglasses, and oneliquid crystal cell is installed on a front surface of each of thepolarizing plates on the right and left sides, to calculate asynchronization signal radiated from an infrared light synchronizationsignal radiator attached along the stereoscopic image display device andreceived by an infrared light synchronization signal receiver placed onan eyeglass frame and detection data of a tilt angle detector placed onthe eyeglass frame, apply a voltage based on data obtained by thecalculation to the liquid crystal cell on the front surface of theeyeglasses to synchronously drive the liquid crystal cell, alternatelyopen and close the right and left visual fields for the stereoscopicimage to separately view the stereoscopic image while causing alight-shielded state at the time of closing the visual fields to alwaysreach its maximum even when the eyeglasses are tilted duringappreciation, to prevent a crosstalk from occurring.
 4. Stereoscopicimage appreciation eyeglasses for appreciating a stereoscopic image by astereoscopic image display device of a type of alternately displayingright and left images composing the stereoscopic image by time divisionwith linear polarized light, the amplitude direction of which is onedirection, the stereoscopic image appreciation eyeglasses beingconfigured so that polarizing plates in the same direction arerespectively arranged side by side in right and left visual fields ofthe eyeglasses, and a total of six liquid crystal cells, three liquidcrystal cells overlaid on the right side and three liquid crystal cellsoverlaid on the left sides each including a visual field opening/closingliquid crystal cell, a left tilt correcting liquid crystal cell forcorrecting, when the eyeglasses are tilted leftward, the tilt, and aright tilt correcting liquid crystal cell for correcting, when theeyeglasses are tilted rightward, the tilt, respectively, on frontsurfaces of the polarizing plates, to receive a synchronization signalradiated from an infrared light synchronization signal radiator attachedalong the stereoscopic image display device by an infrared lightsynchronization signal receiver placed on an eyeglass frame tosynchronously drive the visual field opening/closing liquid crystalcells, alternately open and close the right and left visual fields forthe stereoscopic image to separately view the stereoscopic image whiledriving and adjusting the left tilt correcting liquid crystal cells orthe right tilt correcting liquid crystal cells installed one over theother on each of the right and left visual fields of the eyeglasses, asneeded, using detection data of a tilt angle detector placed on theeyeglass frame so that a light-shielded state at the time of closing thevisual fields always reaches its maximum even when the eyeglasses aretilted during appreciation, to prevent a crosstalk from occurring.
 5. Atilt angle detector for tilt correction of stereoscopic imageappreciation eyeglasses, the tilt angle detector comprising a tilt angledetecting liquid crystal cell, an infrared polarizing filter, and aninfrared sensor, and being configured as its functions so that theamplitude direction of polarized infrared light radiated from astereoscopic image display device and incident on a liquid crystal cellis controlled to a state orthogonal to the polarization direction of theinfrared polarizing filter by applying a voltage to the tilt angledetecting liquid crystal cell, a voltage to be applied to the tilt angledetecting liquid cell, i.e., a checking voltage changes depending on thetilt of the eyeglasses, the applied voltage is gradually raised, anoutput of the infrared sensor rapidly decreases, to enter a non-outputstate at the time point where the amplitude direction of the polarizedinfrared light enters a state orthogonal to the polarization directionof the infrared polarizing filter, and a voltage applied to the liquidcrystal cell at the time point is sampled, to detect a tilt angle.
 6. Atilt angle detector for tilt correction of stereoscopic imageappreciation eyeglasses, the tilt angle detector being configured sothat a first tilt angle detecting liquid crystal cell and a second tiltangle detecting liquid crystal cell are installed one over the other toenlarge an operation range, an infrared polarizing filter and aninfrared sensor are arranged in this order behind the first and secondtilt angle detecting liquid crystal cells, polarized infrared lightradiated from a polarized infrared light synchronization signal radiatorin a stereoscopic image display device is transmitted by the first tiltangle detecting liquid crystal cell and the second tilt angle detectingliquid crystal cell after its optical rotation has been adjusted therebyby applying a voltage to an electrode of the first tilt angle detectingliquid crystal cell and an electrode of the second tilt angle detectingliquid crystal cell after coupling the electrodes in series or inparallel or sequentially applying a voltage to the electrode of thefirst tilt angle detecting liquid crystal cell and the electrode of thesecond tilt angle detecting liquid crystal cell, the applied voltage isgradually raised, an output of the infrared sensor rapidly decreases toenter a non-output state at the time point where the amplitude directionof the polarized infrared light enters a state orthogonal to thepolarization direction of the infrared polarizing filter, and a voltageapplied to the liquid crystal cells at that time point is sampled, todetect a tilt angle.
 7. A tilt angle detector for tilt correction ofstereoscopic image appreciation eyeglasses, the tilt angle detectorcomprising infrared polarizing plates arranged side by side with theirrespective polarization directions tilted in opposite directions using avertical line as an axis of symmetry and infrared sensors respectivelyinstalled at positions just behind the infrared polarizing plates, andbeing configured so that symmetry between the tilts of the infraredpolarizing plates is destroyed when the eyeglasses are tilted so that adifference occurs in an amount of transmission of polarized infraredlight serving as a basis for tilt correction, which has been radiatedfrom a stereoscopic image display device, and the difference is used asan electrical output using the infrared sensor, to detect a tilt angle.8. The stereoscopic image appreciation eyeglasses according to claim 2,3, or 4, wherein a slot for a diopter correction lens holder and a lenspressing spring are provided on a front surface or a rear surface ofeach of the right and left visual fields of the eyeglasses.
 9. Thestereoscopic image appreciation eyeglasses according to claim 2, 3, or4, being configured so that a diopter correction lens to be attached toa slot for a diopter correction lens holder in the stereoscopic imageappreciation eyeglasses and having both its ends, as viewed from a frontsurface, formed in the shape of a circular arc and having its lower endformed in the shape of a curve or a straight line having a largercurvature than that of the circular arc at both the ends is detachablyattached.